Lifespan: Why We Age—and Why We Don't Have To

by David A. Sinclair

After twenty-five years of researching aging and having read thousands of scientific papers, if there is one piece of advice I can offer, one surefire way to stay healthy longer, one thing you can do to maximize your lifespan right now, it’s this: eat less often.

The important thing is not just what we eat but the way we eat. As it turns out, there is a strong correlation between fasting behavior and longevity in Blue Zones such as Ikaria, Greece, “the island where people forget to die,” where one-third of the population lives past the age of 90 and almost every older resident is a staunch disciple of the Greek Orthodox church and adheres to a religious calendar that calls for some manner of fasting more than half the year.16 On many days, that means no meat, dairy products, or eggs and sometimes no wine or olive oil, either—for some Greeks, that’s just about everything. Additionally,

A popular method is to skip breakfast and have a late lunch (the 16:8 diet). Another is to eat 75 percent fewer calories for two days a week (the 5:2 diet). If you’re a bit more adventurous, you can try skipping food a couple of days a week (Eat Stop Eat), or as the health pundit Peter Attia does, go hungry for an entire week every quarter. The permutations of these various models for extending life and health are being worked out in animals and will be worked out in people, too. The short-term studies are promising.

Red meat also contains carnitine, which gut bacteria convert to trimethylamine N-oxide, or TMAO, a chemical that is suspected of causing heart disease.

When we substitute animal protein with more plant protein, studies have shown, all-cause mortality falls significantly.

individuals who exercise more—the equivalent of at least a half hour of jogging five days a week—have telomeres that appear to be nearly a decade younger than those who live a more sedentary life.31

There’s really no way around this. We all need to be pushing ourselves, especially as we get older, yet only 10 percent of people over the age of 65 do.32 The good news is that we don’t have to exercise for hours on end. One recent study found that those who ran four to five miles a week—for most people, that’s an amount of exercise that can be done in less than 15 minutes per day—reduce their chance of death from a heart attack by 40 percent

and all-cause mortality by 45 percent.33 That’s a massive effect.

The big shock was that the health benefits were remarkably similar no matter how much running the people had done. Even about ten minutes of moderate exercise a day added years to their lives.35 There is a difference between a leisurely walk and a brisk run, however. To engage our longevity genes fully, intensity does matter. Mayo

If you make food filling but not as calorific, some of the health benefits are lost. Being hungry is necessary for CR to work because hunger helps turn on genes in the brain that release longevity hormones, at least according to a recent study by Dongsheng Cai at the Albert Einstein College of Medicine.

Would a combination of fasting and exercise lengthen your lifespan? Absolutely.

exposing your body to less-than-comfortable temperatures is another very effective way to turn on your longevity genes.

Eating less at each meal, moving more, and focusing on plant-based foods are much safer options. Another thing you can try is activating the mitochondria in your brown fat by being a bit cold. The best way to do this might be the simplest—a brisk walk in a T-shirt on a winter day in a city such as Boston will do the trick.

Supplements are far, far less regulated than medicines, so if I do take a supplement, I look for a large manufacturer with a good reputation, seek highly pure molecules (more than 98 percent is a good guide), and look for “GMP” on the label, which means the product was made under “good manufacturing practices.” Nicotinamide riboside, or NR, is converted to NMN, so some people take NR instead of NMN because it is cheaper. Cheaper still are niacin and nicotinamide, but they don’t seem to raise NAD levels as NMN and NR do.